The subject invention relates to a socket for interconnecting a chip with a printed circuit board.
Due to the small center-line spacing between electrical pads of a chip, it is known in the art to provide a substrate having resilient leads extending from one side of the substrate, and solder balls on the opposite side of the substrate, where the leads and the solder balls are electrically interconnected through vias in the substrate. Such a substrate can include a housing therearound, whereby the housing will provide a location for a chip to be interconnected to the substrate leads.
However, existing connection systems provide that the leads extend entirely through the associated housing, and thus present the possibility for damage to the leads. This damage can occur in multiple ways, but it is common that the leads are damaged when the chip is placed adjacent to the housing, in that the leads must be resiliently biased downwardly in order to align the chip with an associated housing. Secondly, as the leads extend proud of the housing, it is common that tooling or other mechanisms will grab the exposed leads and bend or break them from the substrate.
Thus, a need exists in the marketplace to provide a solution to the above-mentioned shortcomings.
The objects of the invention have been accomplished by providing a socket for interconnecting a chip to a substrate, where the chip includes pads thereon and the substrate includes leads extending upwardly therefrom and are profiled to contact the pads. The socket comprises a housing having an upper chip receiving face, a lower substrate receiving face, and a plurality of longitudinally extending slots extending between the upper chip receiving face and the lower substrate receiving face. The socket includes at least one resilient arm extending downwardly therefrom for contacting the substrate.
In the preferred embodiment of the invention, the housing includes marginal side walls and marginal end walls, with the longitudinally extending slots being formed by ribs extending between the end walls. The resilient arm extends from one of the marginal side walls, and preferably comprises a pair of resilient arms along the one side marginal wall. The housing further comprises a post attached to each of the marginal side walls, and resilient arms extending therefrom. The resilient arms extend parallel to the marginal side walls. Each resilient arm includes a foot portion adjacent to a free end of each arm, the foot portion having a lower surface, which is resiliently movable from a first free state position below the lower substrate receiving face to a resiliently deformable position planar with the lower substrate receiving face. Each foot portion includes a substrate retaining member.
In another aspect of the invention, a socket is provided for interconnecting a chip to a printed circuit board, where the chip includes pads thereon. The socket comprises a housing having an upper chip receiving face, a lower substrate receiving face, and a plurality of lead receiving openings extending between the upper chip receiving face and the lower substrate receiving face. A substrate is provided having a plurality of leads extending upwardly therefrom and positioned within the lead receiving openings, with contact ends of the leads positioned below the chip receiving face. A resilient spacer is positioned between the substrate and the housing, the spacer being deformable to a position where the leads extend through the chip receiving face.
In the preferred embodiment of the invention, the spacer is comprised of at least one resilient arm extending downwardly therefrom for contacting the substrate. The housing includes marginal side walls and marginal end walls, and the lead receiving openings are defined as longitudinally extending slots extending between the end walls. The resilient spacer is defined as a resilient arm extending from one of the marginal side walls. The socket preferably further comprises a pair of resilient arms along the one marginal side wall. The socket comprises a post attached to each of the marginal side walls, and resilient arms extending therefrom. The resilient arms extend parallel to the marginal side walls. The resilient arm includes a foot portion adjacent to a free end of each arm, and the foot portion has a lower surface, which is resiliently movable from a first free state position below the lower substrate receiving face to a resiliently deformable position planar with the lower substrate receiving face, and each foot portion includes a substrate retaining member. The substrate has a lead contact field and openings along side marginal edges thereof, and the substrate retaining members comprise posts interferingly positioned within the openings.
Preferably, the housing includes marginal side walls and marginal end walls, and the upper chip receiving face is defined by a recess into the housing defining inner peripheral edges in the marginal side walls and marginal end walls. The socket further comprises locating members positioned adjacent the recess for positioning the chip in the housing in juxtaposition with the leads.